body{
    margin: 0;
}
.wrap {
    width: 540px;
    height: 258px;
    margin: 100px auto;
}
.coupon-wrap {
    width: 540px;
    height: 258px;
    background-color: #4090e4;
    padding: 20px;
    box-sizing: border-box;
}
.coupon-wrap .coupon-bd {
    position: relative;
    width: 500px;
    height: 218px;
    padding:15px;
    background-color: #d3ba3b;
    box-sizing: border-box;
}
.coupon-wrap .coupon-bd:after,
.coupon-wrap .coupon-bd:before{
    content:'';
    position: absolute;
    top:5px;
    width: 0;
    height:100%;
}
.coupon-wrap .coupon-bd:before{
    border-right: 10px dotted #4090e4;
    left: -5px;
}
.coupon-wrap .coupon-bd:after{
    border-left: 10px dotted #4090e4;
    right: -5px;
}
.coupon-wrap .coupon-bd .coupon-canvas{
   width: 100%;
   height: 100%;
}
.coupon-wrap .coupon-bd canvas{
    background:url(../images/coupon.png);
    background-size: 470px 188px;
    background-repeat: no-repeat;
}